Fitness Training Expert aims to provide top quality fitness training advice, exercise information and educational resources for all fitness enthusiasts.  Expert fitness advice SEARCH THIS SITE FACEBOOK BRIDGEFIT ARTICLES   Resistance training for fat loss This article explores briefly the effect that resistance training has on fat loss. This article explores fat loss from a hormonal perspective, focussing the attention on cortisol and human growth hormone. It discusses the case against low intensity exercise and briefly explores how stress can make fat loss more difficult. It then further goes on to look at how high intensity resistance training can have a more postive effect for long term weight loss. The role that extra muscle mass has on metabolism and the metabolic effects of resistance training and high intensity exercise will be discussed in future fitness articles. The case against low intensity, steady state exercise… High volume steady state aerobic activity can cause a catabolic response in the body. The body loses lean muscle mass. This is brought on in part due to the cortisol release. Cortisol is a hormone that is also released at times of stress. There are numerous journals with inferences to the role that cortisol plays within the body, certainly indicating health implications. Ottosson et al (2000) indicate that cortisol is an “antilypolytic agent”. This means that Cortisol is giving our cells the message to hold on to their fat stores. I also found another source, (only the abstract however), which looked at the cortisol response in individuals of varying body fat percentages during a first time sky dive (Mujica-Parodi et al, 2009). This study suggested that a higher body fat percentage correlates with greater cortisol release in times of stress. This is an extremely brief and somewhat over simplified explanation of how exercise increases cortisol levels, and the negative effect this may have on fat storage and degradation of muscle tissue. Cortisol is not all bad, it is a hormone vital for our health and survival. I am just exploring some of the negative effects. Unfortunately the way some people lead their lives through necessity or choice can lead to a constant fight or flight state. Cortisol levels can be elevated in these conditions, and in its glucose sparing role can cause breakdown of our muscle mass to create energy. Tremblay et al (2005) indicate that beyond 80 minutes of running there is a shift to a more catabolic hormonal environment. Catabolic exercise is not going to produce favourable results where weight loss is concerned. I remember a while ago working in a gym and a young lady used to visit 5 maybe 6 days a week. She was in the gym for 2-3 hours on occasions. It would be cross trainer, treadmill, bike and the whole sequence repeated for the duration of her workout. Knowing what I know now (which is only a little on this subject) about the hormonal responses to exercise she was really a living example of this. Her weight never changed, her body fat was deposited around her abdominal region and if anything seemed to increase month by month. Cortisol can have this effect on the body, essentially storing more fat in the abdominal region. This has been identified also by notable experts such as Charles Poliquin. His work has led to an understanding that manipulation of diet can affect hormone balance and suggests dietary recommendations based on where body fat excess is stored. Have a look at biosignature modulation for more details. Perhaps we can spot reduce fat after all??? When I was studying on one course it was frequently mentioned about reducing stressors in ones life to improve performance in training programs. Stress can consume our lives too much; if we have not attempted to reduce our stressors in some way then exercise is just going to add to this.  For weight loss training we need to eliminate our stressors wherever we can and ensure our training favours an anabolic response not a catabolic one. To lose body fat we need to hold on to our muscle mass, and ideally create some more! The case for high intensity resistance training… Not only can cortisol levels be elevated by aerobic exercise but cortisol can also increase with short rest periods and high volume resistance training, the type of training which favours a fat loss response! So if it is released from lots of aerobic training and also from resistance training yet is potentially degrading to our muscle tissues then where am I going with even mentioning this?  Well Beachle and Earle (2008) indicate that although long term high levels of cortisol have adverse affects, the short term effects of cortisol release from resistance training actually play a role in the remodelling of muscle tissue. That is a good thing! Lean muscle burns calories! Just remember to plan lower volume “rest days” into your overall training plan to help prevent chronic elevated cortisol levels. As well as a short term cortisol increase, growth hormone is also released in response to certain resistance training protocols. A greater activation of anaerobic glycolysis and lactate formation when training results in greater release of this hormone within the body. One study looking at growth hormone levels in people who could not produce lactate in response to exercise (McArdles disease) found that 9 out of 11 failed to demonstrate any appreciable growth hormone increase. This is not a huge cohort for a study but does support what is known about growth hormone release. Growth hormone increases amino acid transport across cells, decreases glucose utilization, increases protein synthesis, and importantly for fat loss increases utilization of fatty acids and fat breakdown (lipolysis). The intensity, volume and rest periods of a resistance training program can affect the growth hormone response. Multiple sets of moderate to heavy resistance with short rest periods are key to maximising the growth hormone response. In favouring resistance training for its effect on fat loss many people reading this will worry that they won’t be getting any aerobic training for the heart. In other words worried they won’t be doing any “cardio”. I think it was Alwyn Cosgrove who correctly pointed out that all training is cardiovascular – our heart beats to pump blood around our body in response to a demand placed upon it. If you have never tried intense resistance training, in a metabolism boosting manner utilising whole body exercises then perhaps you should. Then come and tell me if your heart is beating faster! References: Beachle, T. R. and Earle, R. W, (2008) Essentials of Strength Training and Conditioning, NSCA. Champaign; Human Kinetics. Mujica-Parodi L.R, Renelique R, Taylor MK (2009) Higher body fat percentage is associated with increased cortisol reactivity and impaired cognitive resilience in response to acute emotional stress. International Journal of Obesity (Lond) Jan; 33(1):157-65. Malin Ottosson, Peter Lönnroth, Per Björntorp and Staffan Edé (2000) Effects of Cortisol and Growth Hormone on Lipolysis in Human Adipose Tissue. The Journal of Clinical Endocrinology & Metabolism Vol. 85, No. 2 799-803 Tremblay MS, Copeland JL, Van Helder W. Influence of exercise duration on post-exercise steroid hormone responses in trained males. European Journal of Applied Physiology. 2005 Aug; 94(5-6):505-13. Godfrey RJ, Whyte GP, Buckley J, Quinlivan R. The role of lactate in the exercise-induced human growth hormone response: evidence from McArdle disease. British Journal of Sports Medicine. 2009 Jul; 43(7):521-5. Related Resistance Training Articles